Symptomatic Growth of a Thrombosed Persistent Sciatic Artery Aneurysm after Bypass and Distal Exclusion

A 71-year-old woman presented with an enlarging mass in the right buttock, with pain and tingling sensation in sitting position. Five years ago, she was diagnosed with acute limb ischemia due to acute thrombosis of right persistent sciatic artery (PSA), and she underwent successful thromboembolectomy and femoro-tibioperoneal trunk bypass. Computed tomography angiography revealed a huge PSA aneurysm (PSAA). During the previous bypass, the distal popliteal artery was ligated just above the distal anastomosis to exclude the PSAA, whose proximal end was already thrombosed. However, PSAA has grown to cause compression symptoms, and the mechanism of aneurysm growth can be ascribed to type 1a or type 2 endoleak. In order to relieve the compression symptoms, aneurysm excision was performed without any injury to the sciatic nerve. A postoperative tingling sensation due to sciatic-nerve stimulation in the supine position resolved spontaneously one month after surgery.